CURLOPT_REDIR_PROTOCOLS_STR - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_REDIR_PROTOCOLS_STR,
                          char *spec);

Pass a pointer to a string that holds a comma-separated list of case insensitive protocol names (URL schemes). That list limits what protocols libcurl may use in a transfer that it follows to in a redirect when CURLOPT_FOLLOWLOCATION(3) is enabled. This option allows applications to limit specific transfers to only be allowed to use a subset of protocols in redirections.

Protocols denied by CURLOPT_PROTOCOLS_STR(3) are not overridden by this option.

By default libcurl allows HTTP, HTTPS, FTP and FTPS on redirects (since 7.65.2).

These are the available protocols:

DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPE, RTMPS, RTMPT, RTMPTE, RTMPTS, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET, TFTP, WS, WSS

You can set "ALL" as a short-cut to enable all protocols. Note that by setting all, you may enable protocols that were not supported the day you write this but are introduced in a future libcurl version.

If trying to set a non-existing protocol or if no matching protocol at all is set, it returns error.

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to restore to internal default.

The application does not have to keep the string around after setting this option.

HTTP, HTTPS, FTP and FTPS (Added in 7.65.2).

Older versions defaulted to all protocols except FILE, SCP and since 7.40.0 SMB and SMBS.

This functionality affects http only

int main(int argc, char **argv)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    /* pass in the URL from an external source */
    curl_easy_setopt(curl, CURLOPT_URL, argv[1]);

    /* only allow redirects to HTTP and HTTPS URLs */
    curl_easy_setopt(curl, CURLOPT_REDIR_PROTOCOLS_STR, "http,https");

    /* Perform the request */
    curl_easy_perform(curl);
  }
}

Added in curl 7.85.0

Returns CURLE_UNKNOWN_OPTION if the option is not implemented, CURLE_UNSUPPORTED_PROTOCOL if a listed protocol is not supported or disabled, CURLE_BAD_FUNCTION_ARGUMENT if no protocol is listed else CURLE_OK.

CURLINFO_SCHEME(3), CURLOPT_DEFAULT_PROTOCOL(3), CURLOPT_PROTOCOLS(3), CURLOPT_PROTOCOLS_STR(3), CURLOPT_REDIR_PROTOCOLS(3)

curl_easy_setopt(3), CURLOPT_FOLLOWLOCATION(3), CURLOPT_PROTOCOLS_STR(3), CURLOPT_REDIR_PROTOCOLS(3), CURLOPT_UNRESTRICTED_AUTH(3), CURLOPT_URL(3), libcurl-security(3), libcurl-symbols(3).